The respiratory system

The respiratory system is responsible for the intake of oxygen and the removal of carbon dioxide from the body. The main components  of the respiratory system are the lungs, the diaphragm and the intercostals.

The location of the lungs

The lungs are located in the thoracic cavity, behind the sternum and the ribcage. 

The direction of airflow within the respiratory system

Nose and mouth→Pharynx (throat)→Larynx (voice box)→Trachea→Bronchi/bronchus→Bonchioloes→Alveoli


The diaphragm contracts and descends drawing air into the lungs..


The diaphragm relaxes and ascends and pushes air out of the lungs.

Tidal volume

The amount of air inhaled/exhaled in one breath.

Minute ventilation (MV)

The amount of air inhaled/exhaled in 1 minute.

Breathing rate (BR)

The number of breaths taken in 1 minute.


The movement of gas from an area of high concentration to an area of low concentration.

Gaseous exchange

The process where oxygen is exchanged for carbon dioxide.

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